Browsing by Author "Cheng, Yu-Jui"

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Application Dependency Tracing for Message Oriented Middleware
(2014)
Wu, Li-Juin
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Li, Hong-Wei
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Cheng, Yu-Jui
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Wu, Yu-Sung
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Lin, Houcheng
Software defined infrastructure greatly reduces the deployment cost of distributed applications. Many distributed applications employ message oriented middleware (MOM) for the integration of heterogeneous components and to achieve scalability and fault tolerance. The structure of a distributed application can be very complex. In addition, the asynchronous message delivery model of MOM further complicates the runtime behavior of a distributed application. To diagnose a faulty distributed application, one often needs to determine the dependences of its messages, and by extension, the dependences of its components. We propose Message Tracer to identify the message dependencies of a MOM-based distributed application. Message Tracer sniffs the network traffic of MOM and uses knowledge of message broker protocols to establish the dependencies. Message Tracer makes no assumption on the application threading model and incurs negligible performance overhead. Message Tracer correctly identified 95% of the dependencies for the common use cases and 75% of the dependencies when the system was under extreme stress.
Exploiting Neigborhood Similarity for Virtual Machine Migration over Wide-Area Network
(2013)
Lai, Hsu-Fang
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Wu, Yu-Sung
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Cheng, Yu-Jui
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資訊工程學系
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Department of Computer Science
Conventional virtual machine (VM) migration focuses on transferring a VM's memory and CPU states across host machines. The VM's disk image has to remain accessible to both the source and destination host machines through shared storage during the migration. As a result, conventional virtual machine migration is limited to host machines on the same local area network (LAN) since sharing storage across wide-area network (WAN) is inefficient. As datacenters are being constructed around the globe, we envision the need for VM migration across datacenter boundaries. We thus propose a system aiming to achieve efficient VM migration over wide area network. The system exploits similarity in the storage data of neighboring VMs by first indexing the VM storage images and then using the index to locate storage data blocks from neighboring VMs, as opposed to pulling all data from the remote source VM across WAN. The experiment result shows that the system can achieve an average 66% reduction in the amount of data transmission and an average 59% reduction in the total migration time.